Electric storage battery.



PATENTED FEB. 27, 1906.

H. H. PORTER. ELECTRIC STORAGE BATTERY.

APPLICATION FILED SBPT.2I.1903.

lf i UNITED STATES PATENT oFFIoE.

HARRIS HARDING PORTER, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO RHODE ISLAND ELEOIROMOBILE COMPANY, OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF MAINE- ELECTR C STORAGE BATTERY.

. Specification of Letters Ifatent. Application filed September 21, 1908. Serial No 178,921.

Patented Feb. 27, -1 906.

To all. whom it may concern:

Be it known that I, HARRIS HARDING PORTER, of Providence, in the count of Providence and State of Rhode Island, ave invented certain new and useful Improvements in Electric-Stora e Batteries, of which the following is a speci cation. I

The object of this invention is'to provide a separator for secondary-battery plates-which shall prevent 'short 'circuiting and to the greatest possible extent disintegration of the battery.

Another object of this invention is to provide a separator. which will permit the use of battery-plates having a very open grid and a maximum extent of active material exposed to the exciting liquid,-the construction of the separator preventing the active material from falling away from the grid, while allowing, free access of the exciting liquid to the active material.

)Another object of this invention is to pro-.

wide a separator which shall make the internal resistance of the battery equal throughout all parts thereof, shall be porous, sufficiently flexible to conform to the changes in the bat- I tery-plates from 'heat, expansion, &c. and.

yet bind the perforated non-conducting sheet firmly and evenly against the adjacent face of the battery-plate.

To accomplish these objects, I make my separator of a sheet or stri of wood having parallel plane portions an parallel grooves therein, arranged alternately on opposite sides thereof, the plane portions being substantially wider than the grooves which separate them and each said plane ortionbeing directly opposite a groove on t e other face I of bar of the sheet. This separator used by itself in conjunction with plates of secondary batteries 1s far superior to those with which I am ac uainted and when used in connection wit a erforated non-conducting sheetsay rubber-presents the following decided advantages: It enables us to use a very open gridfgivmg a much greater amount of exposed active surface, and permits the use of a ver thin separator and perforated sheet,-

there y decreasing the internal resistance of the battery and increasing the output. Mali ing the plane surfaces wider than the grooves, moreover, ives between the thin grooved portions of the separators solid verticallportions 17 of the full thickness of the separator, thereby insuring an equally-distributed internal resistance to pressure at all points in the battery and preventingunequal Working of different portions of the plate-surfaces, for it will be readily seen that should the grooves be wider than the plane surfaces or even of. the same width as said surfaces those portions of the separator marked 17 17 in Fig. 2 would be substantially absent, and the spaces now filled by such portions would be substantially empty spaces, which fulfil no useful purpose. On the other hand,

result in a weakening of the se arator and in permitting the active materia on ex ansion active material to fall .down between the same and the separator, all as appears below. The

separator allows of its being made stronger and yetflexlble enough to conform to changes in the state of the battery arising from heat,

0t or cause, asabove stated. In addition to the advantages enumerated above this separator accomplishes a result absolutely essential to the life and proper working of the battery and allows the employment in batteries exposed to hard usage, such as automobiling, of plates that cannot now be used. Bythis ismeant plates Whose external'surface is practically all active material.

Unless the perforated non conducting sheet is pressed and bound firmly and flatly against .theactive material there will result short-circuiting and deterioration. In my separator the relatively wide plane surfaces 'hold and bind the perforated sheet against the active material practically as flat and firmly as though the separator were a continuous flat surface, while at the same time nels for the circulation ofthe exciting liquid and developed gases.

I do not wish to be understood as claiming herein Wooden se arators as such provided with vertical surfaces and grooves, but as claiming separators having plane surfaces substantially wider than the grooves, as set forth above.

In the drawings, Figure 1 is a perspective view of a battery, partly broken away, eniomitting said portions 17 17 would therefore to press in the perforated sheet and a low the greater Width of the plane portions of the ex ansion of active material, or from any the narrower grooves furnish vertical chanbodying my improvement. Fig. 2 is an enlarged cross-section illustrating the relative thickness of the plates and the arrangement of separators combined therewith. Fig. 3 is the weight of metallic lead in the grids and correspondingly increase the amount and surface exposure of. active material held thereon by the separators. This reduction in the weight of the grids, not herein separately claimed, is in part accomplished by making the negative pole-plates 4 and 5 materially thinner thanthe-positive pole-plates 6., the outermost negatives being, say, forty per cent. less and the intermediate negatives twenty per cent. less in thickness than the several )ositives. Furthermore, in all the "lead gri s the intermediate lon itudinal bars 7 are of less thickness than t eir marginal frames 8 and transverse bars 9, such reduction in thickness reaching, preferably, an average of forty per cent. This leaves a substantial thickness of the active material cov ering and exposed to the electrolyte over such thinner bars, which are still of suflicient capacity to carry the current, while the frame and transverse bars resist the lateral pressure. I, however, leave one or more of the longitudinal bars, preferably the central one, 10, of full thickness to hel bear the pressure and prevent buckling. n-the thin outermost negatives 4 these bars are alternately thick and thin. The marginal framebars 8 of.all the'plates have an inwardly-extending rib midway between their edges, which helps support the active material. It is feasible and practicable in my battery to thus expose broad surfaces of the active material outside of the supporting frame-bars, because such material is held'in place and protected against disintegration by my improved separators bearing laterally u on such surfaces, yet admittingthe electro yte thereto.

Between the successive plates of the battery I interpose'three-ply separators comprising a middle layer 11 of wood deeply,

grooved vertically on opposite sides in alternate planes and a finely-perforated thinnonconducting sheet 12, preferabl of hard rubber, each side of said layer an in immediate contact with the adjacent battery-plates. The wooden layers are by preference onecighth inch thick, with grooves 13 an eighth inch wide, a sixteenth deep, and separated by seven-sixteenths of an inch of fiat surface. When we use the specific shape of separator disclosed in Fig. 2, this gives in cross-section the effect of rectangular corrugation, with vertical channels 13 for the electrolyte and also affords appreciable relief from the pressure of expansion due to any cause in the use of the battery.

The wood separators 11 extend slightly beyond the edges of the several plates and materially below them at bottom 1n order to guard against short-circuiting. To accomplish this readily, I may form notches 15 in the lower edges of the woodensheets at the oints where plates and separators rest at bottom on raised ribs 16, formed on the bottom of the jar. These notches ermit the wood separators to project beyon the other parts resting on said ribs. (See Fig. 1.)

I claimas my invention- 1. In a storage battery, a separating device for thesuccessive plates, consisting of a thin layer of wood having parallel rectangular vertical grooyes arranged alternately'on its-opposite sides, and between them, relatively wide fiat spaces, each such s ace'being directly opposite a groove on t e other face of said layer, such se arator being notched at one end to receive t e supporting- .rib in the battery-jar whereby such separator may extend below the adjacent lates, to

regent short-circuiting, substantia ly as set ort J 2. In a storage battery, a separating device for the successive plates consisting of a thin layer of wood havin parallel vertical grooves arranged alternate on its opposite sides, and, betweenthem, p ane surfaces sub: stantiall wider than'said grooves, each such surface eing directl opposite'a groove on the other face of said ayer.

3. In a storage battery, a separating device for the successive plates, consisting of a thin layer ofv wood havingparallel vertical igrooves arranged alternately on its opposite sides, and, between them, plane surfaces substarftiall wider than said grooves, each such surface eing directly opposite a groove on the other face of said layer, in combination with a perforated sheet of non-conducting material, as and for the purpose set forth.

4. A porous separatorfor secondary-battery plates, having on its faces a series of flat surfaces and ooves, said surfaces being substantially 'wi lar than said'grooves, and the surfaces on one face being opposite the grooves on the other face.

5. A porous separator for secondary batteries, having on each of its faces alternate plane surfaces and grooves, the plane surfaces being substantially wider tharr the grooves and the plane surfaces on one face being opposite grooves on the other.

6. The combination of a non-conducting l separator having oil its faee'al ternate plane 10 perforated sheet adapted to hold the active surfaces and grooves, the plane surfaces bematerial in position with a porous separator in substantially wider than the grooves. having on each 'ofitsfaoes alternate plane n testimony whereof'I have aflixed my 5 surfacesand grooves, the plane surfaces besignature in presence of two Witnessesii ing-substantially wider than the grooves. HARRIS HARDING PORTER.

7. The combination of a porous sheet 'Witnesses:

adapted to maintain the active material in HENRY M. Boss, J12, position, with a porous secondary-battery LEONARD W. HORTON. 

